Various types of tests related to patient diagnosis and therapy can be performed by analysis assays of a sample of a patient's infections, bodily fluids or abscesses. Such patient samples are typically placed in sample vials, extracted from the vials, combined with various reagents in special reaction cuvettes or tubes, incubated, and analyzed to aid in treatment of the patient. In typical clinical chemical analyses, one or two assay reagents are added at separate times to a liquid sample, the sample-reagent combination is mixed and incubated within a reaction cuvettes. Analytical measurements using a beam of interrogating radiation interacting with the sample-reagent combination, for example turbidimetric or fluorometric or absorption readings or the like, are made to ascertain end-point or rate values from which an amount of analyte may be determined using well-known calibration techniques.
Although various known clinical analyzers for chemical, immunochemical and biological testing of samples are available, analytical clinical technology is challenged by increasing needs for improved levels of analysis. Due to increasing pressures on clinical laboratories to reduce cost-per-reportable result, there continues to be a need for improvements in the overall cost performance of automated clinical analyzers. In particular, sample analysis continuously needs to be more cost effective in terms of reducing consumables or the cost thereof required for each and every reaction assay.
A positive contributor to reducing cost-per-reportable result is the ability to repeatedly perform reaction assays in reaction cuvettes that are washed or otherwise cleaned after a first reaction is completed and between subsequent reaction assays. What has been overlooked, however, in many such cleaning systems, is that washing techniques are not fully capable of restoring a cleaned used cuvette to the degree of cleanliness of an unused cuvette, most especially if reagent residues from a preceding assay have wicked upwards along an inside wall of the reaction cuvette onto its top surface or even onto an outside surface. Thus, for reaction cuvettes to be useful in a cuvette-rewashing system, it is advantageous that capillary wicking, a process in which fluids inside a cuvette flow upwards along interior walls, be totally eliminated or significantly minimized. In addition, elimination of wicking positively contributes to the accuracy of reaction assay measurements because the integrity of the reagents and sample originally dispersed into the cuvette is maintained; i.e., no liquids have capillary wicked out of the original mixture so that integrity of the reaction constituents is maintained.
U.S. Pat. No. 4,902,479 discloses use of a barrier structure extending along the surface of a cover member to inhibit premature mixing of constituents inside proximate chambers due to wicking movement of constituents stored in one chamber.
U.S. Pat. No. 5,571,479 discloses an analysis cuvette in which plane-parallel side-walls and the bottom of the cuvette which are used as measuring windows for spectrophotometrical absorbance and fluorescence polarization measurements of the cuvette's contents.
U.S. Pat. No. 5,658,532 discloses an analysis cuvette having a rectangular top portion on the top, a cylindrical portion below the top portion, and a lower rectangular portion so as to not unfavorably rotate when measuring the absorption of light transmitted through the cuvette's contents.
U.S. Pat. No. 6,214,626 discloses an analysis cuvette which permits simultaneous use as reaction vessel for taking up one or more reaction liquids, for incubating and storing these liquids and for carrying out optical measurements so that analysis may be free of carryover.
U.S. Pat. No. 6,249,345 discloses an analysis cuvette having pairs of planar-parallel optical windows opposite one another, wherein the distance between one pair is different from the distance of another pair in order to make available differing layer thickness of the sample fluid for measurements of the cuvette's contents.